What is a SequenceFile?

What is a SequenceFile?
A . A SequenceFile contains a binary encoding of an arbitrary number of homogeneous writable objects.
B . A SequenceFile contains a binary encoding of an arbitrary number of heterogeneous writable objects.
C . A SequenceFile contains a binary encoding of an arbitrary number of WritableComparable objects, in sorted order.
D . A SequenceFile contains a binary encoding of an arbitrary number key-value pairs.
Each key must be the same type. Each value must be same type.

View Answer

Answer: D

Explanation:

SequenceFile is a flat file consisting of binary key/value pairs.

There are 3 different SequenceFile formats:

Uncompressed key/value records.

Record compressed key/value records – only ‘values’ are compressed here.

Block compressed key/value records – both keys and values are collected in ‘blocks’ separately and compressed. The size of the ‘block’ is configurable.

Reference: http://wiki.apache.org/hadoop/SequenceFile